First of all, relax!

Your doctor confirmed (already in the hospital) that your baby is not jaundiced and that his weight is fine. The mohel has visited you, checked the baby and instructed you how to prepare him for the brit. Perhaps you also advised with a pediatrician. You have washed your baby and dressed him up. Perhaps you decided to give him an infant’s dose of a pain reliever approximately half an hour before the brit (upon instruction from a doctor). You might have fed the baby just before the brit (as directed by the mohel).

Don't forget to pack in your diaper bag 4 cloth diapers, 5 disposable diapers, a bottle and pacifier (even for a baby who doesn't usually use them), and of course a camera (except on Shabbat or festivals). Make sure to also bring a pillow for carrying the baby, 2 tallits (for the father and the sandek), kipahs, wine (sweet, in a closed bottle), a wine cup and if you have a family tradition - fragrant myrtles for the blessing of "besamim." Check that there will be a special decorated chair -'Elijah's chair', upon which the sandek will sit and hold the baby during the ceremony. It is preferable to dress the baby in a two piece outfit, and not in overalls so that it won't be necessary to undress him fully before the circumcision.